The dialysis phenomenon is used in the medical and biological field either for taking samples of substances secreted in living tissue in order to analyze the substances for diagnostic purposes, or else to deliver a drug or a medicine to living tissue. The dimensions of the dialysis probe must naturally be small so as to avoid damaging biological tissue, and this is of major importance when working on brain tissue. That is why the present invention relates more specifically to microdialysis.
Presently available microdialysis probes comprise two parallel or concentric dialysis tubes with their distal ends that come into contact with biological tissue being provided either with an external protection device (cf. GB-A-1 595 079, for example) or else with a mount which surrounds the dialysis membrane (FR-A-2 537 000).
Such devices for protecting the membrane which is itself very fine and fragile suffer from the drawback of damaging biological tissue since they cannot be made with small dimensions for reasons relating both to problems of making such protection devices and to problems of fixing the membrane which must naturally be fixed in a manner which is perfecting reliable.